The use of antibiotics in aquaculture

The vast majority of antibiotic treatments in aquaculture are administered to populations. Although there is some use of bath administration in 

Prophylactic treatments of populations are undertaken for a variety of reasons or to address a variety of real or perceived problems. These can be usefully designated as specific risk prophylaxis, general risk prophylaxis and growth promotion. 

Specific risk prophylaxis can usefully describe treatments given when it is possible to predict, with some confidence, that a population will face a risk of a specific bacterial infection at a specific time. It should be noted that the protection of the host population will be only for the period of the therapy and, possibly, for a few days after. This form of prophylaxis, therefore, is likely to be effective if and only if the occurrence and particularly the timing of the infection and, therefore, the disease risk, can be accurately predicted. Provided these conditions are met, however, specific risk prophylaxis can be considered as prudent and may be economically justifiable. 

These considerations become particularly important when the issue of placing orally administered antibiotic therapy on a rational foundation is addressed. It is difficult to develop rational, prudent and optimised therapies when we do not know in which sub-population we expect the antibiotic to exert its beneficial effect. 

2 The role of antibiotic therapy in the control of disease losses 

---